High-voltage circuit interrupter



Jan. 27, 1948. R. H. EARLE 2,434,994

HIGH VOLTAGE CIRCUIT INTERRUPTER Filed March 8, 1944 2 Sheets-Sheet l INVENTOR. 010% b. ffl/Plf Jan. 27, 1948. R. H. EARLE HIGH VOLTAGE CIRCUIT INTERRUPTER 2 Sheets-Sheet 2 Filed March 8, 1944 IMA H /M Mimi &. /6./////4.//// r/// v///////////////////r////////////6V\ r7770 A/fY.

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Patented Jan. 27, 1948 UNITED PATENT OFFICE LHIGH=VOIJTAGE C RCUIT INTERRUPTER Ralph H. Earle, Wanwatosa, 'Wis., assignor to Dine Material Gomneny, South Milwaukee, Wis. a-corporationwof Delaware Application March 8, 1944,:Se1ia-INO. 525,484

or mixed with the ionized gases-produced by :the

arc.

Further objects of this invention are to provide a high voltage circuit "interrupter in which the main arc is interrupted by a powerfu'l'cross blastof gas and at thesame time an auxiliary arc is established in series with the main arc and is elongated so as to prevent restriking after the main arc has been extinguished, and in which the cross blast produces-aconcentrated effect at a localized point.

In greater detail; further objects of thisi-nve-n- .tion are .to "provide a high voltage, heavy duty circuit interrupter :in which a main arc is produced in :a relatively short @channelpart; f which extends into and crossways of' :,a zrelatiilsely along channel, through (the'la'tter lotwhich :a powerful blast of arc extinguishing has 'isprojected, .such gas :beingliberated ifrom material which is acted upon'byan auxiliaryarqgthe deyice being seconucted that he m inand auxiliary-arc-are kept separate at all times lthe auxiliary are beingzin series with the main arc :and:being-mechanically established whereas the main, arc is es ablished asa result .of the fusing of'zaiuseF-lln-k, the-auxiliaryare being; very-quick ,ielongatedito prevent ,restri-kingoi the; main :arceailter the main: (arc has been-:internupted,theeconstruction ibeingsuch that, the movable parts are -1 relativel small mass andare-quicklyiacceleratedland withdrawn .to a considerable idistanceiromitheir 'nonmal position to thus prov-idea substantial and effective gap. lhereby securing the protection againstra striking,

.Further objects lare to providea -.constm ction in which refill .unit lor renewableluni-tsrare em, lployed, in whichthernaior portion-10f the, pparatus mayxbe usedover. and over again andrin which. th refill. ,units are ,so, constructed that when. they. are returnedio; the facto s-u; ac-major 2 portion of such units may be used in the construction of a new refill unit.

In circuit interrupters in which a fuse link is employed it has been found that the fuse link heats up to a considerable extent when it is loaded to somewhere near its rated capacity. In some-of the priordevices the fuse link has been located in proximity to the material adapted to liberate gas when acted upon by an arc and consequently the heat from the fuse link prior to rupture often causes an uncertainty or unreliability in "the operation of the apparatus,

This invention is designed to overcome the above noted defects, and further objects of this invention are to provide a high vol age, heavy duty iuse construction in which none of the heat afrom :the fuse link when it is carrying substantiallyits rated capacity of current is transmitted to the material which liberates the gas for extincguishi-ng the arc, in which this material is carriedat a point remote from the fuse link and is also insulated from a relatively heavy metal rod lor conductor which does not heat up to any sub- ,stantiaL-degree when --the fuse link is loaded to its rated capacity and which, therefore, is reliable and certain in its operation.

Further objects are 3130 provide a heavy duty, highuoltagefuse construction in which a simple type ioi'fuse link-maybe employed which is adapted to rupture on overload and establish the main are, and in which mechanical means are em- ;ployed :for establishing an auxiliary arc and for drawing ther auxiliary are into proximity to the gas liberating material, and also in which such mechanical means-is withdrawntoa remote point sons to prevent rest-riking of eitherarc after the main :arc has once been interrupted, the construction being such that the main arc is kept transversely of thegas blast channel and is not allowed to combine with'the-auxiliary are so that :the Ema-in. arc is thus kept in -position where it is ibnost readily extinguished by the powerful cross 1 last.

Further objects-are to provide a construction which issturdy; in "which the refill uni-ts may be handled without requiring any unusual care on the part of the -lineman, and in which such re;- newable units may be veryeasily substituted for a pneviously used vunit.

Embiodimentsiof the invention are shown int-he (accompanying drawings; in which:

Figure 1-;=ls-a-side eleva:tion of the circuit interrupter, such viewbeing partly in a section.

Figure Z-isailongitudinalsectional viewthrough the deylce ;;such;-view. being; partly broken away.

Figure 3 is a sectional view on the line 3--3 of Figure 2.

Figure 4 is a sectional view on the line 4--4 of Figure 2.

Figure 5 is a fragmentary view of a modified form of the invention.

Figure 6 is a sectional view through a modified form of a fiber plug.

Referring to the drawings, it will be seen that the circuit interrupter comprises upper and lower stationary terminals indicated respectively at I and 2 and supported by insulators 3 and 4 carried by a suitable base portion 5. The circuit interrupter is removably and pivotally supported from the lower contact. For example, the lower contact may be provided with a pair of hook like portions 6 within which trunnions 'l rigid with the circuit interrupter are positioned. Any other suitable support for the lower end of the circuit interrupter could be employed. The trunnions I in the form shown are rigidly formed with the lower terminal 8 of the circuit interrupter.

The circuit interrupter is provided with an upper terminal 9 which is provided with outwardly projecting pins I!) on opposite sides thereof which hook behind depressed portions I I of a pair of spring arms I2 which are pivotally carried by the rigid member I3 of the upper terminal, such spring arms flaring outwardly and upwardly as indicated at I4.

The particular construction of this upper contact may be varied as desired. Preferably the spring arms I2 are U-shaped and bear against downwardly slanting cam portions I5 which are provided with stops I6 at their lower ends to limit the downward rocking motion of the spring arms I2, such spring arms being urged downwardly by the cam action of the cam portions I5. This construction forms the subject matter of the patent to Will am O. Schultz, No. 2,357,772 of September 5. 1944. for Cut-out construction.

The circuit interrupter comprises two main portions. an upper portion A and a lower portion B. The portion A is the renewable portion and the portion B and the remaining parts of the circult interrupter are adapted to be used over and over again with successively substituted renewable ort ons A. suitable inte locking means hereinafter described being provided for detachab'y lockin the main portions together. The lower portion B of the circuit interrupter comprises a composite tube which may be composed of an outer Bakelite tube IT with a fiber inner tube or lining l8. The upper portion A comprises a composite tube which mav have an outer Bakel te tube I9 and an inner fiber tube or lining 20. The two main portions of the apparatus are removably coupled together by means of a union like structure in which the lower knurled nut 2| revolubly carried b the lower tube is screw threaded onto a screw threaded nip le or co lar 22 rigid with the upper tube or renewable unit, a suitable gasket 23 being interposed between the two units or main portions A and B. Obviously the nut 2I could be carried by the upper portion A and the collar by the lower portion B if desired.

The upper unit or renewable or refill unit carries the upper terminal 9 of the device. This terminal is provided with an outwardly projecting integral tubular portion 24 which is externally screw threaded and receives the apertured metal cap 25. The upper terminal 9 is also provided with a rigidly positioned threaded pin 26 which receives one end of the fuse link, such fuse link being preferably composed of a flexible leader 2'! terminating in a fitting 28 apertured to slip over the pin 26 and being looked in place by means of a nut 29. The flexible leader extends through the apertured metal cap 25 and through the fiber tube 30 which lines the metal tube 24. The fiber tube 30 is fitted to or seats against the inner fiber tube 20in a gas tight manner and is held in this position by means of the screw threaded apertured metal cap 25.

The inner end of the flexible leader is joined to a fusible section 3I and a strain wire 32. The other end of the strain wire and fusible section are joined to an upstanding intermediate terminal or member 33. The member 33 is a metal member integral with the metal ring like portion 34, such ring like portion being provided with a plurality of upwardly extending spring contact fingers 35 which are urged into engagement with the retractable plunger or metal rod 36 by their inherent resiliency supplemented by an annular helical spring 31 as shown in Figures 2 and 4. The retractable rod 36 is provided with a strain piece or fiber end portion 38 which is apertured at its upper end and through which the strain wire 32 passes. Preferably the fusible section 3| is bent upwardly and remains out of contact with the fiber piece 38. The upper end of the rod 36 is reduced and screw threaded into the lower end of the fiber piece 38.

The retractable rod or plunger 36 is constantly urged downwardly by means of a relatively heavy tension spring 39. Preferably this tension spring is secured at its upper end to an upper head piece 40 removably screw threaded onto the lower end of the rod 36 and to a lower head portion M on which a disk like nut 42 is screwed, these heads being electrically connected to a flexible leader 39'. The disk like nut 42 is held in clamped engagement with the lower terminal 8 by means of the lower metal cap 43. It is preferable to provide a threaded opening 44 in the lower head piece 4| to facilitate repositioning of such head piece during refusing in a manner hereinafter to appear. From the construction thus far given, it is apparent that the retractable plunger 36 is constantly urged downwardly and would move downwardly except that it is held by the strain wire 32. The flexible leader 2! is held snugly so as to hold the strain wire 32 relatively tight and minimize the sagging thereof due to the downward pull of the plunger 36. Of course, a certain amount of sagging does occur, for example, as shown in Figure 2, but this is not objectionable.

The lower end of the refill unit is provided with a screw threaded plug 45 of fiber which is screwed tight y into the lower end of the upper unit. This fiber tube is provided with a reduced downwardly extending portion 46 which fits within the lower composite tube. The fiber plug is also provided with a slot 41 at its lower end which slidably receives a pin 48 carried by the rod 36 to prevent relative rotation of the rod 36 with respect to the refill unit when the upper head 40 is screwed onto the lower end of the rod.

A container such as the torus-shaped glass member 49 is positioned within the refill unit and contains a gas liberating material such as the liquid 50. The rod 36 extends freely through this container and is provided with a heat insulating sheath 5| which maybe of laminated Bakelite or of paper glued to or otherwise tightly secured to the rod and adapted to freely travel downwardly with the rod when the rod is retracted in a manner hereinafter to appear. The container 49 is held between upper and lower cushioning gaskets tainerlll ir 51 'lhe' portion 34 has an upper shoulderedfface upon which a metal washerl557restsl Above washer a fiber block or ping'meememe estis. positionedl This plug lilie 'fnenibehis' provided with anaperture' 5;! therethroilgh withinfwhicfi the fiber strain piece 38 is positioned; -"llhis. aper tare extends upwardly and joins an' uiiv'vard1 5, v flaring apertures; formed in th -filbjerpliig 55. The: upper portion of the fiber pmgi 5:6"iss .0tt6.

transversely as indicated. atT-59 and asf'sho'wfi parupper end by' means' of a fiber- 1 sleeve or spacing member 60 which in turn. is held in place by Bakelite cap. 5]; screwthreaded one theupper end time refilliunit Bakelite cap is provided with 'an"iriternalannular groove 62, so asto pro vide aweaken'edf centralportion so that the cen-v t'raliportion "will be blown outwardly to free": venting of the "eeviceu bn'invented,

When an overload occurs," the fusible section 3 is ruptured and. instantly the strain. wire 32] is ruptured; Thefle'xibl ilead erfifis"i'rnrnediately time 'lateralliffroni theld evice through the tube 30;?" At the same time the rod 36 isr'ele'ased and is drawn downwardly with'ektreme "rapidity by means ofthe spring; 39, thus establishing an auxiliary arc from the contaetfingers 3510 the upper end of the-fod w- This a umnar arc is: drawn dhwnwa'rdly into proximity -t'o'the gas-liberating materialandlbreaksthe'coritainr 49am liberates aTquan'tity' of are extinguishing. 'gas which passes upwardly through the atrmrei 5'l transversely o'ffthe m'ain'arc andfis vented outwardly through the flaring vent passage .SHfthlis 'tmwm transversely of the main arc and 'quiclgly eit'inguishin-g' the 'main arc. the weakened'centr'al portion of: the cap having b own ofiand providing free venting. The proportionfeff the parts is stih that the plunger 36 is never withdrawn below-theplug 4 5 The downwaidmotionl of the plunger it? performs an additionahfunction in that it' extends the auxiliary arc and thus lengthens'me distance between the rod 36 and the spring, fingeis'ae so as topre'ven't restriking. after the 'm'aiatrehas been extinguishedf W It is to be notedpartioul'arly that a violent blast of gas is projected transversely or crossways of 'the'mai'n arc-and the are extinguishing efiect as a result cfs'uch violent transverse blastis confined to a restricted zon'e'so as to have its maximum'effect at this selected'po'int and" thusinsure extinguishing ofthe mairi'arc; When the main arc has been. extinguishedQit will -be 'foun d that the plunger 36 isfulllxiretracte'd and :consequently there is no danger ofrestriking though the path where the main arc had'ex'istedis relat'ifvel'yshort. l l fte'r'th'e 'device'has operated, thecircuit interrupter'maybe removed and ma-y'beremsed; In refusing, anew refilhor'renewable tinit' is" subs Q tl itt'edffoi' the previously usedunitg. This is easily;

accomplished by removing, the'lowe'r screw cap 43 and screwing the thre'tded'bnd of an in'stru me'nt, not shown, into the" threaded ap'erture "44 and pulling the lower head 14 l between a slight distance. Thereafter the disk like nut 42' are moved and the headfM isallowed to be retracted inwardly by the spring 36; Thereafter the union nut Z-l isunscrewed andthe upperu nit is 'bcdili? removed. Subsequently the upp'erhe'ad llqisIunscrewed from the rod 36. Anew unitisther'i phsi t, m eezthe fi r ead 0 qn otheiroq a new hit; the p n 4am the Si n lTpreent' I aq t ti lth 'rm ifif v h t ilq .o, th upper unit. After" this has'beenagco nplished,

. theupperun-it or refill unit is pesitioned'on' the lgiwer unit. wi he reducedlportion ifipf'theplug;

.5:- ..i n. a l m -"t cbfmnosi w r ime T8 T. Thereafter the nut 2l' of'the .ilhiqri '1 mai were o'fjsuch units can/be used, in making we; "While it'i s preterable to provide the slot 59 in the upper insulating plug or block '56, as this slot 25 facilitate theaslsernb ih of the refill unit at the fact neverthelesjsit is withinthe province of this 1 vention 'to'dis'pense with the transverse slptfiflfand te use instead a transverse hole align 1r; with'thefhiile through the fiber sleeve an though he assembling of the device is complicatedtbythis construction. Thej'fiber plug with the transversefhole therethrough in place or the slj is illustrated in section in Figure 6 and is indicated by the reference-character 56',

I1 nve tion meta s? t r; msor e ample asshownin Figure 5, a looped cord or lieavy thread t3 maybe employed to initially hold the plunger 36: in position. Thi thread or cord Q PRQ Q eve t e. tr in, W re( 32 n is of n ea m n wi h h wardly moped u i section 3|; Theiripper end of the rod 36' is pro vid with; anopening for the reception oft-the ooped: ara thr a This, o d hr ad tie iis made or insulating cornbustihle material and is partially or hompletely destroyed when the fuse r immered- 'Itis to be ncted frpm reference tcFigure- 3that theflopen ng 5] ,for th'e violent blast oftgases is largen-thar ithe transverse slot, 59, By having the openingjjflarger than theslot 59, there is no tendencjferjthe'arc to pass around the upward ia i gas s. nd; il e. t u h stead thenpward blast of gases e xting uishes the are'in a reliable and eifective manner even; for h'ealvyj voltage 'heayy duty circuits and under e'ev re l e It' s t il Fe a h rans er e. pa e e Qr hemai am s el el hor and o seguently high pressure cannotbuildvup in this passage as it isfreely vented laterally to the out sideair, In additiontothis, thepressure within the efi ll unit is resisted by the composite tube c sreinforcedby the-surrounding upper tervlower ring; like portion 22 .of the us imparting-considerable strength M M ed and ledjnto proximity'tolgas fiber ati -ng InaeriaL and ;is elongatedpto preventcre= Strik n after the main arc has been extinguished.

It will be seen further that the operation of the apparatus is very rapid even under high voltage, heavy overloads.

It is to be noted also that the refill units may be very easily substituted for previously used units and that no particular skill is required in their installation.

It will be seen also that the major part of the circuit interrupter can be used over and over again and in addition to this, that a large part of the refill units returned to the factory may be used in making new refill units.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A circuit interrupter comprising a body portion having an elongated auxiliary arc channel and a relatively short main arc channel extending transversely of said auxiliary arc channel, said body portion having venting means located on one side of said main arc channel, gas liberating means within said auxiliary arc channel located on the other side of said main arc channel adapted to liberate gas when acted upon by an are, means adapted to interrupt a circuit and establish a main arc in said main are channel, and means in said auxiliary arc channel for establishing an auxiliary arc in proximity to, said gas liberating means in series with said main arc and for elongating said auxiliary are.

2. A circuit interrupter comprising a body portion having an elongated auxiliary arc channel and a relatively short main arc channel, means adapted to interrupt a circuit and establish a main arc in said main arc channel, gas liberating means in said auxiliary arc channel adapted to liberate gas when acted upon by an are, means in said auxiliary arc channel for establishing an auxiliary-arc in proximity to said gas liberating means in series with said main arc and for elongating said auxiliary arc, and means for guiding the liberated gas under pressure into said main are from said auxiliary arc channel.

3. A circuit interrupter comprising a body portion having an elongated auxiliary arc channel and a relatively short main arc channel, means adapted to interrupt a circuit and establish a main arc in said main arc channel, gas liberating means in said auxiliary arc channel adapted to liberate gas when acted upon by an are, means in said auxiliary arc channel for establishing an auxiliary arc in proximity to said gas liberating means in series with said main arc and for elongating said auxiliary arc, and means for guiding the liberated gas transversely across said main are.

4. A circuit interrupter comprising a body portion having an elongated auxiliary arc channel and a relatively short main arc channel extending transversely with respect to said auxiliary arc channel, said body portion having venting means for said auxiliary arc channel located on one side of said main arc channel, gas liberating means in said auxiliary arc channel located on the other side of said main arc channel and adapted to liberate gas when acted upon by an arc, a fuse link in said main arc channe1 extending transversely across said auxiliary arc channel and adapted to establish a main arc in said main arc channel on the occurrence of an overload, and biased means normally restrained by said fuse link and located in said auxiliary arc channel and adapted to establish an auxiliary arc in series with said main are upon rupture of said fuse link and to draw said auxiliary are into proximity to said gas liberating means and to extend said auxiliary arc.

5. A circuit interrupter comprising a body portion having a relatively long auxiliary arc channel extending lengthwise thereof and having a relatively short main arc channel extending transversely thereof and freely open at one end, a terminal adjacent the open end of said main are channel, a fuse link extending from said terminal through said main arc channel transversely of said auxiliary arc channel and adapted to interrupt a circuit on overload and form a main arc transversely of said auxiliary arc channel, said main arc channel having an expulsion action, gas liberating means adapted to liberate gas when acted upon by an are located in said auxiliary are channel, means adapted to form an auxiliary arc in said auxiliary arc channel in proximity to said gas liberating means upon rupture of said fuse link, and means for directing the liberated gas transversely across said main arc.

6. A circuit interrupter comprising a body portion having a main arc channel and an auxiliary are channel, gas liberating means in said auxiliary arc channel adapted to liberate gas 1 when acted upon by an are, a fuse link in said main arc channel adapted to rupture on overload and establish a main arc in said main arc channel, biased movable means in said auxiliary arc channel normally restrained by said fuse link and adapted to establish an auxiliary arc in series with said main arc and in proximity to said gas liberating means upon rupture of said fuse link, heat insulating means surrounding said biased movable means, and means for directing the liberated gas into said main are from said auxiliary arc channel.

7. A circuit interrupter comprising a body portion having a main arc channel and an auxiliary arc channel, gas liberating means in said auxiliary arc channel adapted to liberate gas when acted upon by an are, a fuse link in said main arc channel adapted to rupture on overload and establish a main arc in said main arc channel, biased movable means in said auxiliary arc channel normally restrained by said fuse link and adapted to establish an auxiliary arc in series with said main arc and in proximity to said gas liberating means upon rupture of said fuse link. heat insulating means carried by and surrounding said biased movable means, and means for directing the liberated gas into said main arc from said auxiliary arc channel.

8. A circuit interrupter comprising a body portion having a main arc channel and an auxiliary arc channel, gas liberating means in said auxiliary arc channel adapted to liberate gas when acted upon by an arc, a fuse link in said main arc channel adapted to rupture on overload and establish a main arc in said main arc channel, biased movable means in said auxiliary arc channel for establishing an auxiliary arc in series with said main arc and in proximity to said gas liberating means upon rupture of said fuse link, insulating means mechanically interposed between said fuse link and said biased movable means for mechanically restraining said biased movable means while said fuse link is intact, and means for directing the liberated gas into said ma n arc.

9. A circuit interrupter comprising a, body porarc channel, biased movable means garter when acted upon by anjarc,;a fuse link in, said main arc channel adapted to rupture on overload and establish a main arc 'insaid main'arc channel, biased movable means in said auxiliaryarc channel forestablishing an auxiliary arc in, series with said mainfarcand proximity tosaid' gas liberating means upon rupture'of said v use link,

insulating means ,mechanically interposed between said fuse link and said biased movable means for mechanically restraining said biased movable means While said fuse link is intact,

means for directing the liberatedgasinto said main arc, and means for elongating at least one ofsaid arcs. :j

10, A circuit interrupter comprising a body portion having a main arc channelvand an auxiliary arc channel, gas liberatingim'eans .in said auxiliary arc channel adapted to liberate as when acted upon by an arc, a fuse link in said main, arc channel adaptedto rupture .on overload and establish a main arc insai'dfrnain in said auxiliary arc channel for establishing an auxiliary arc in series with said main arc and in proximity to said gas liberating means upon rupture of said fuse link, insulating means mechanically interposed between said fuse link and said biased movable means for mechanically restraining said biased movable means while said fuse link is intact, means for directing the liberated gas into said main arc, and means for elongating said auxiliary arc to prevent restriking after said main arc has been extinguished.

11. A circuit interrupter comprising a body portion having a main arc channel and an auxiliary arc channel, gas liberating means in said auxiliary arc channel adapted to liberate gas when acted upon by an arc, a fuse link in said main arc channel adapted to rupture on overload and establish a main arc in said main arc channel, biased movable means in said auxiliary arc channel for establishing an auxiliary arc in series with said main arc and in proximity to said gas liberating means upon rupture of said fuse link, insulating means rigid with and carried by said biased movable means and mechanically interposed between said fuse link and said biased movable means for mechanically restraining said biased movable means while said fuse link is intact, and means for directing the liberated gas into said main arc.

12. A circuit interrupter comprising a body portion having a main arc channel and an auxiliary arc channel, gas liberating means in said auxiliary arc channel adapted to liberate gas when acted upon by an arc, a fuse link in said main arc channel adapted to rupture on overload and establish a main arc in said main arc channel, biased movable means in said auxiliary arc channel for establishing an auxiliary arc in series with said main arc and in proximity to said gas liberating means upon rupture of said fuse link, combustible insulating means mechanically interposed between said fuse link and said biased movable means for mechanically restraining said biased movable means while said fuse link is intact, and means for directing the liberated gas into said main arc.

13. A circuit interrupter comprising a body portion havin a main arc channel and an auxiliary arc channel, gas liberating means in said auxiliary arc channel adapted to liberate gas when acted by an arc, a" fuse link in said main arc channel adapted to rupture on overload and'establish a main arc in said main. arc channel, "said fuse link including a fusible seotion'and a strain wire, a first'terminal, 'saidfuse linkhaving one end connected tojsaid first terminalfa conductor, within. said body 'portionjel-ectrically connectedto theother end'fofrsaid fuse link, biased movable means normally electrically connected tojsaid conductor and located in said auxiliary arcLchanneI for establishing an auxiliary fare in ii erieswithsaid main arc and in proximity to said gas liberating means uponrupt'ure of said fuse link, a second terminal electrically. connected to saidlibias'edjmovable means, insulating means mechanically interposedbetween said strain wire and said biased movable. meansfor mechanically "restrainin isaidlbiased movable means while said fuse, link isuintact, Ian'd,.means for directing the liberated gas intosaid'main arc.

} 14. A circuit interrupter comprising abody portion having a jrnai'nj arc channel and an auxiliary arc channel gas liberatingmeans in said and establish a main arc in said main arc channel, a first terminal, said fuse link having one end connected to said first terminal, a conductor within said body portion electrically connected to the other end of said fuse link, biased movable means normally electrically connected to said conductor and located in said auxiliary arc channel for establishing an auxiliary arc in series with said main arc and in proximity to said gas liberating means upon rupture of said fuse link, a second terminal electrically connected to said biased movable means, insulating means mechanically interposed between said fuse link and said biased movable means for mechanically restraining said biased movable means while said fuse link is intact, and means for directing the liberated gas into said main arc.

15. A circuit interrupter comprising a body portion having a main arc channel and an auxiliary arc channel extending transversely of said main arc channel, said main arc channel having an open end and said auxiliary arc channel having venting means adjacent one end, a terminal adjacent the open end of said main arc channel, a fuse link having one end connected to said terminal and located within said main arc channel and adapted to interrupt a circuit on overload and form a main arc in said main arc channel transversely of said auxiliary arc channel, gas liberating means located in said auxiliary arc channel adapted to liberate gas when acted upon by an arc, said gas liberating means and said venting means being located on opposite sides of said main arc channel, biased mechanically movable means electrically connected to and normally restrained by said fuse link and adapted to form an auxiliary arc in said auxiliary arc channel in proximity to said gas liberating means upon rupture of said fuse link, and a second terminal electrically connected to said biased mechanically movable means.

16. A circuit interrupter comprising two main portions: one of said main portions including a body portion and retracting means carried by said body portion; the other of said main portions constituting a renewable portion and including an insulating member having an auxiliary arc channel and a main arc channel extending transversely across said auxiliary arc channel, gas

liberating means adapted to liberate gas when acted upon by an are located in said auxiliary arc channel, a fuse link in said main arc channel adapted to rupture and form a main arc transversely of said auxiliary arc channel on overload, and a retractable member within said auxiliary arc channel detachably attached to the said retracting means of said first portion and normally restrained by said fuse link and adapted to draw an auxiliary are into proximity to said gas liberating means upon rupture of said fuse link; said two main portions having interengaging portions for detachably locking said two main portions together.

17. A circuit interrupter comprising two main portions: one of said main portions including a body portion and retracting means within said body portion; the other of said main portions constituting a renewable portion and including a second body portion having an auxiliary arc channel extending lengthwise thereof and a main arc channel extending transversely thereof across said auxiliary arc channel, gas liberating means adapted to liberate gas when acted upon by an link in said main arc channel adapted to rupture and form a main arc transversely of said auxiliary arc channel on overload, and a retractable member within-said auxiliary arc channel detachably attached to the said retracting means of said first portion and normally restrained by said fuse link and adapted to draw an auxiliary are into proximity to said gas liberating means and to elongate said auxiliary arc upon rupture of said fuse link; said two main portions having interengaging portions for detachably locking said two main portions together.

RALPH H. EARLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 465,893 Fisher Dec. 29, 1891 2,091,430 Conrad Aug. 31, 1937 2,100,413 Steinmayer Nov. 30, 1937 Re. 20,450 Hill July 20, 1937 1,859,377 Boudion May 24, 1932 2,386,886 Earle et a1 Oct. 16, 1945 

